1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
#include <iostream>
using namespace std;
class Binary
{
public:
Binary() = default;
Binary(Binary const &other)
{
cout << "Copy constructor\n";
}
Binary(Binary &&tmp)
{
cout << "Move constructor\n";
}
Binary &operator+=(Binary const &rhs) &&
{
cout << "Move +=\n";
return *this;
}
Binary &operator+=(Binary const &rhs) &
{
cout << "Copy +=\n";
Binary tmp(*this);
std::move(tmp) += rhs;
swap(tmp);
return *this;
}
void swap(Binary &rhs)
{}
};
Binary &&operator+(Binary &&lhs, Binary const &rhs)
{
cout << "move operator + called and returns\n";
return move(move(lhs) += rhs);
}
Binary &&operator+(Binary const &lhs, Binary const &rhs)
{
cout << "copy operator + called\n";
Binary tmp(lhs);
cout << "copy operator + returns\n";
return move(tmp) + rhs;
}
int main()
{
Binary d1;
d1 + d1 + d1;
cout << "========\n";
Binary{} + Binary{} + Binary{};
}
|
